In Situ Formation of Heterojunction in Composite Lithium Anode Facilitates Fast and Uniform Interfacial Ion Transport

Abstract Lithium metal is a highly promising anode for next‐generation high‐energy‐density rechargeable batteries. Nevertheless, its practical application faces challenges due to the uncontrolled lithium dendrites growth and infinite volumetric expansion during repetitive cycling. Herein, a composite lithium anode is designed by mechanically rolling and pressing a cerium oxide‐coated carbon textile with lithium foil (Li@CeO 2 /CT). The in situ generated cerium dioxide (CeO 2 ) and cerium trioxide (Ce 2 O 3 ) form a heterojunction with a reduced lithium‐ion migration barrier, facilitating the rapid lithium ions migration. Additionally, both CeO 2 and Ce 2 O 3 exhibit higher adsorbed energy with lithium, enabling faster and more distributed interfacial transport of lithium ions. Furthermore, the high specific surface area of 3D skeleton can effectively reduce local current density, and alleviate the lithium volumetric changes upon plating/stripping. Benefiting from this unique structure, the highly compact and uniform lithium deposition is constructed, allowing the Li@CeO 2 /CT symmetric cells to maintain a stable cycling for over 500 cycles at an exceptional high current density of 100 mA cm −2 . When paired with LiNi 0.91 Co 0.06 Mn 0.03 O 2 (NCM91) cathode, the cell achieves 74.3% capacity retention after 800 cycles at 1 C, and a remarkable capacity retention of 81.1% after 500 cycles even at a high rate of 4 C.